Theoretical simulations of infrared spectra and multidimensional proton tunneling in hydrogenbonded materials

International Conference on Smart Materials & Structures

June 15 -17, 2015 Las Vegas, USA

Marek Janusz Wojcik

Posters-Accepted Abstracts: J Material Sci Eng

Abstract :

Theoretical model is presented for the X-H(D) stretching vibrations in hydrogen-bonded systems. The model takes into account an adiabatic coupling between the high-frequency X-H(D) stretching and the low-frequency intermolecular X...Y stretching modes, linear and quadratic distortions of the potential energy for the low-frequency vibrations in the excited state of the X-H(D) stretching vibration, resonance interactions between hydrogen bonds, and Fermi resonance between the X-H(D) stretching and the overtone of the X-H(D) bending vibrations. The effects of deuteration and temperature on spectra are successfully reproduced by the model. Comparison between experimental and theoretical spectra is presented for hydrogen- bonded crystals, liquids, gaseous complexes, as well as for ices and aqueous ionic solutions. Multidimensional proton tunneling in symmetric hydrogen-bonded systems is described by two-dimensional model potentials. The potentials have been fitted to quantum-mechanically calculated two-dimensional grid of energies, and used to analyze proton dynamics in tropolone. The model PES quantitatively reproduces experimentally observed promotion of the tunneling by the excitation of the planar modes and suppression by the excitation of the out-of-plane modes.